For the compacting of earth there exists a plurality of equipment based on various types of compaction gauges or measuring devices. Documentation is normally made by means of devices showing a summarized picture of the result. At the same time, the corresponding data is stored in some suitable medium. Further processing and entering of the obtained measured results in a suitable data base can then be performed in a personal computer arranged at another location. When compacting asphalt, the tested methods from the compacting of earth cannot be transferred without due consideration. This is true for primarily two reasons:
1. It does not yet exist any functioning compaction measuring device showing the result of the compacting of the asphalt layer as measured continuously directly from the compacting machine. The nuclear measurement devices which are known and are to be mounted on the compacting machine itself, have a limited use since they require long integration time to produce accurate information and since the use thereof is impeded by the restrictions prescribed by the authorities owing to the radiation. PA1 2. In compacting asphalt it is not possible to control the movement of the compacting machine, so that a large rectangular surface could be compacted to a finished state before the compacting machine is used for compacting another large rectangular area. Instead, the compacting of asphalt is performed continuously accompanying the deposition of the asphalt by an asphalt paving machine which can move forward continuously with an approximately uniform velocity over a distance which often several hundreds of meters. The paving operation is normally stopped only at breaks and if the supply of new asphalt compound fails.
In compacting asphalt the compacting machine follows the paver machine according to a scheme having limited possibilities of variation. A postcompaction of some areas where a too low compaction degree has been detected can only be performed if more than one compacting machine is available.
It is also advantageous to have access to equipment which can document the compacting work performed which together therewith stores all relevant operational parameters.
Even if there would be limited possibilities of correcting mistakes by having the compacting machine afterwards compact badly worked asphalt portions it may be a great value if the system successively produces continuous information by which it is possible to adjust those operational parameters so that the result of the compacting work can successively approach an optimum result. Adjustable parameters can be the distance or stroke length over which the compacting machine travels before it reverses its running direction to move in the opposite direction; the interior operational parameters of the compacting machine; and the velocity of the asphalt paver.